Identifying and Resolving Generic Router Problems
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Scenario #2
This next scenario is a little more difficult. Look at Figure 5.2 to get a picture
of the network that you will troubleshoot. Host Z is trying to FTP a file to
Host A, but Host Z is unable to do so.
F I G U R E 5 . 2
Network diagram for scenario #2
Let's move through the troubleshooting method to solve this problem.
Start by listing your observations.
List Observations
As discussed in Chapter 1, you should define the boundary of dysfunction-
ality, which can be done in several ways. In this scenario, you test by
attempting to FTP to Host A while observing the results.
The first test is an actual FTP attempt. Figure 5.3 shows the results of the FTP
attempt. The software gives you a host unreachable error message, which is an
ICMP response. EtherPeek was used to capture packets in this exchange. The
first packet decode is Host Z sending an FTP connection request.
F I G U R E 5 . 3
FTP attempt failure
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